Lynn4221 - thanks for posting this.
I used VSL#3 for 2 months but it did nothing for me but that doesn't mean it won't help you. I have also read in several places that it is not the amount of bacteria per CPU but whether the particular strain works for you and whether that reaches the place it is needed. And just because a strain is good for one person it doesn't mean it will help another.
Natrens claim that their probiotics have a unique delivery system which places the bacteria where needed. I understand that one needs to take all of their products which are designed to reach the places that need them.
I have been in correspondence with a guy that works in a lab where they study probitiotics and he advises that you should find a good probiotic and take it for 2 to 3 weeks and if it doesn't help then move onto another one untill you find one that works.
Of course human feces contains billions of a complete set of good bacteria (if you have a healthy donor) including many strains that have not yet been discovered by medical science. Human feces are therefore the number one probiotic.